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通过将二茂铁接枝在大分子链上制备了疏水改性支化聚乙烯亚胺(Fc-BPEI),用动态光散射、透射电镜及旋转流变仪研究了其水溶液中大分子的聚集态结构与流变行为.考察了剪切作用、浓度、温度对溶液中大分子结构和形态及流变行为的影响.研究结果表明,二茂铁改性的聚乙烯亚胺分子尺寸明显增大,且随浓度增大体系中大分子逐渐从分子内疏水缔合为主向分子间疏水缔合为主转变,形成分子间缔合体.上述原因使得Fc-BPEI溶液黏度显著增大,但是该体系却呈现典型的牛顿流体特征.对样品进行连续升-降温循环热处理,发现经过升降温处理后的Fc-BPEI体系黏度明显增大,且增幅随热循环次数增加而逐渐减小.动态流变测试结果表明,这种现象缘于热处理使得大分子链缔合方式和形态发生变化,体系中出现穿插于多个分子间缔合体的PEI大分子,产生了类似网络结构的大分子聚集结构.经热处理的Fc-BPEI溶液呈现显著的剪切变稀现象,高浓度溶液的抗剪切能力显著提高.
Hydrophobically modified branched polyethyleneimine (Fc-BPEI) was prepared by grafting ferrocene onto macromolecular chains. The aggregation of macromolecules in aqueous solution was studied by dynamic light scattering, transmission electron microscopy and rotational rheometer. State structure and rheological behavior were investigated.The effects of shear, concentration and temperature on the structure and morphology of the macromolecules and the rheological behavior of the solution were investigated.The results showed that the molecular size of the polyethyleneimine modified by ferrocene was significantly increased , And with the increase of concentration, the macromolecules in the system gradually migrated from the intramolecular hydrophobic association to the intermolecular hydrophobic association to form the intermolecular association. The above reasons make the viscosity of the solution of Fc-BPEI significantly increase, but the system But the characteristics of typical Newtonian fluid are presented.The continuous heating-cooling cycle heat treatment of the sample shows that the viscosity of the Fc-BPEI system increases obviously with the increase of the number of thermal cycles and the dynamic rheological test The results show that this phenomenon due to heat treatment makes the macromolecular chain association and morphology changes, the system appears interspersed with multiple intermolecular PEI macromolecules, resulting in a similar network structure of macromolecules Set structure. Fc-BPEI by solution heat treatment exhibits significant shear thinning behavior, while highly concentrated solutions significantly increased shear resistance.